The Good Old Days

Alvaro de Rujula has posted on the arXiv under the title “Fifty years of Yang-Mills Theories: a phenomenological point of view” some of his recollections from the mid-seventies. These bring back my own memories of taking a course on particle theory from him at Harvard around 1977-78. One amusing aspect of the course was that when introducing a concept carrying someone’s name, de Rujula would always say something like “this is the so-called Weinberg angle, which of course was discovered by Glashow”. In one lecture he did something a bit different, saying something like “this is the Cabibbo angle, which, strangely enough, I think actually may have been discovered by Cabibbo”. de Rujula’s paper contains one of his famous drawings from the period and an amusing picture of Georgi and Glashow arguing. His asides are entertaining, but some so obscure I confess to not knowing exactly what he is referring to.

Today’s arXiv postings also contain a review talk on the state of string theory. It discusses the “landscape” with the comment “However, with such large numbers of vacua involved, one must wonder whether the scheme is at all testable, even in principle.” Normally string theory reviews start by describing the theory as the “only known” or “best candidate” or “most promising” approach to unification. This one replaces those phrases by “dominant framework”, and one certainly can’t argue with that.

9 Responses to The Good Old Days

Well the story is very interesting, and if we ever meet I’ll relate it.

IMO Zweig deserves a great deal of credit – for one thing he wasn’t just thinking about symmetry, but suppressed reactions being explained by new conservation laws. “Aces” implies 4 things, so his idea foreshadowed charm before anyone had heard of strangeness. There is more to the story as told to me, which I would not feel comfortable relating here.

There is the well-known story that Zweig didn’t publish his ideas because that would have meant putting it in a CERN report instead of Physical Review. This recalls Stueckelberg’s diagrams, which he also did not publish, based on the same idea as Feynman’s (backward-in-time -E electron = positron).

I’ve read various versions of the story of Zweig and his “aces”, but don’t know what story you are referring to.

This is something though where I think Gell-Mann deserves the lion’s credit. He (and independently Yuval Ne’eman) was the one to realize strongly interacting particles could be organized using SU(3) representations and got the prediction of the Omega-minus and its mass. I’ve heard that several people claim to have recognized that since you can construct all SU(3) reps out of tensor products of the fundamental 3-dim one, the existence of a fundamental triplet was a natural conjecture. The problem was that you quickly found the charges to be non-integral, disagreeing with experiment. So I think SU(3) was worth a Nobel prize, but after that postulating the existence of the triplet was not such a big deal.

Gell-Mann was involved in another similar story, the V-A theory of weak interactions, where you’ll find a whole bunch of people claiming credit for the idea around the same time.

Actually according to de Rujula, Gell-Mann claims to have discovered the Cabibbo angle, in an obscure footnote. Thus his reference to it as the “funny angle” instead of “Cabibbo angle”. I also remember from long ago Howard Georgi being very amused by a Harvard secretary’s typo in one of his papers. The Cabibbo “angle” had become the Cabibbo “angel”.

“The Second Creation” by Crease and Mann is by far the best book I know of about the standard model and its history, and I recommend it enthusiastically to anyone learning about particle physics.

Re Cabibbo angle. I must confess that I bought Veltman’s book mainly because of the last paragraph – as you can see at the Amazon.com review, he also uses the phrase “not even wrong” about string theory. However, the book contains a lot of amusing stuff. Apparently Gell-Mann insisted on calling it “that funny angle”, so at one conference Cabibbo wrote “Funny Cabibbo” on his name-tag.

Alvaro is a sort of “show bussiness” by himself. I remember him to actually explain the popular “turtles all way down” joke, in a speech to undergraduate/secondary school teachers, adscribing it to himself.

As for Cabibbo angle, a pesky Spanish nuclear physics teacher, recently deceased, is said to have tried to claim discovery. I do not know if Rujula was aware of it, but it could be.

I’m sure just about all theorists are very disappointed that there hasn’t been much of an active interchange between theorists and experimentalists since the 70s. de Rujula himself has pretty much left particle physics and is doing astronomy.

The underlying problems are that the standard model is just too good and progress on getting higher energy accelerators has been slow. If the SSC had been constructed, maybe we would already be well into a new period of exciting experimental results.

That’s a wonderful read. What exciting times! I was just learning calculus “ex curriculis” in those days – I remember some NOVA programs on the Standard Model, and the interviews with Feynman in particular. I can’t remember how I first learned about all this stuff in detail, but I know it was much later – I was really busy working through Sommerfeld’s lectures and deliberately avoided new results that I would not understand yet. In retrospect, the early to mid 80s was a great time in physics history to be in school – funny it didn’t seem that way at the time…

The whole paper is about what got calculated and why. From this day’s perspective – how quaint 🙂

Is there any disappointment that the theory is still in the post-phenomenology phase? Are people surprised that not a great deal more progress has been made since W/Z?